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Flynn PC, Forth JH, Kaufman WR. A comparison of the cuticular properties of argasid and ixodid ticks: Ornithodoros moubata (Argasidae) vs. Amblyomma hebraeum and Ixodes pacificus (Ixodidae). EXPERIMENTAL & APPLIED ACAROLOGY 2020; 82:515-527. [PMID: 33206311 DOI: 10.1007/s10493-020-00566-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/02/2020] [Indexed: 06/11/2023]
Abstract
Ticks (Chelicerata, Ixodida) are blood-feeding ectoparasites believed to have evolved at least about 120 millions of years ago and found worldwide. However, many aspects of their unique life cycle and anatomy, including their mechanical properties, remain to be understood. Here, we compared the mechanical properties of the cuticle of the argasid tick Ornithodoros moubata to those of two species of ixodid tick, Amblyomma hebraeum and Ixodes pacificus that we explored in our earlier studies of the tick exoskeleton. Significant differences were expected given the substantial difference in life cycle, including a five-fold increase during the repeated adult blood meal for female O. moubata vs. 70- to 120-fold during the single feeding of the adult female A. hebraeum and I. pacificus. We demonstrate here that the layered structure and mechanical properties (stiffness and viscosity) of the cuticle show minor differences, but the difference in cuticle thickness is substantial. Ductility is lost during feeding; reduced pH restores ductility. Previous work suggests that this occurs in vivo in engorged ixodid ticks; there is no evidence of this occurring in vivo in O. moubata. Thinning of cuticle in O. moubata fed females is consistent with the predicted stretch of cuticle due to the blood meal; there is no evidence of cuticle synthesis during the short feeding period. Dimensional analysis suggests that the soft feel of argasid ticks is related to cuticle thickness, not cuticle stiffness. Relative to argasid ticks, the hard ixodid ticks accommodate a ca. 20-fold higher size of blood meal by starting with a thicker cuticle and growing much additional cuticle during engorgement.
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Affiliation(s)
- Peter C Flynn
- Department of Mechanical Engineering, University of Alberta, Edmonton, T6G 2E9, Canada.
| | - Jan Hendrik Forth
- Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - W Reuben Kaufman
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2E9, Canada
- Gulf Island Veterinary Clinic, Salt Spring Island, BC, Canada
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Pacheco I, Acevedo P, Prado E, Mihalca AD, de la Fuente J. Targeting the Exoskeleton Elementome to Track Tick Geographic Origins. Front Physiol 2020; 11:572758. [PMID: 33071826 PMCID: PMC7538837 DOI: 10.3389/fphys.2020.572758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/28/2020] [Indexed: 02/03/2023] Open
Abstract
Understanding the origin of ticks is essential for evaluating the risk of tick-borne disease introduction into new territories. However, when collecting engorged ticks from a host, it is virtually impossible to identify the geographical location where this tick was acquired. Recently, the elementome of tick exoskeleton was characterized by using scanning electron microscopy (SEM) and energy dispersive spectroscopy analysis (EDS). The objective of our preliminary proof-of-concept study was to evaluate the use of SEM-EDS for the analysis of tick exoskeleton elementome to gain insight into the tick geographic and host origin. For this preliminary analysis we used 10 samples of engorged ticks (larvae and nymphs of six species from three genera) collected from various resident hosts and locations. The elementome of the tick exoskeleton was characterized in dorsal and ventral parts with three scans on each part using an EDS 80 mm2 detector at 15 kV in a field emission scanning electron microscope. We used principal component analysis (PCA) (varimax rotation) to reduce the redundancy of data under the premise of losing information as little as possible. The PCA was used to test whether the different variables (tick species, stages, hosts, or geographic locations) differ in the composition of exoskeleton elementome (C, O, P, Cl, and Na). Analyses were carried out using SPSS. The PCA analysis explained a high percentage of variance using the first two factors, C and O (86.13%). The first PC (PC-1; 63.12%) was positively related to P, Cl, and Na, and negatively related to C. The second principal component (23.01%) was mainly positively related to C. In the space defined by the two extracted PC (PC-1 and PC-2), the elementome of tick samples was clearly associated with tick species, but not with developmental stages, hosts or geographic locations. A differentiated elementome pattern was observed within Romanian regions (CJ and TL) for the same tick species. The use of the SEM-EDS methodological approach provided additional information about the tick exoskeleton elementome with possible applications to the identification of tick origin host and location.
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Affiliation(s)
- Iván Pacheco
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, Universidad de Castilla-La Mancha, Junta de Comunidades de Castilla-La Mancha, Ciudad Real, Spain
| | - Pelayo Acevedo
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, Universidad de Castilla-La Mancha, Junta de Comunidades de Castilla-La Mancha, Ciudad Real, Spain.,Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Eduardo Prado
- Department of Applied Physics, Faculty of Chemical Sciences and Technologies, Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Andrei Daniel Mihalca
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos, Consejo Superior de Investigaciones Científicas, Universidad de Castilla-La Mancha, Junta de Comunidades de Castilla-La Mancha, Ciudad Real, Spain.,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
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de la Fuente J, Lima-Barbero JF, Prado E, Pacheco I, Alberdi P, Villar M. Anaplasma pathogen infection alters chemical composition of the exoskeleton of hard ticks (Acari: Ixodidae). Comput Struct Biotechnol J 2020; 18:253-257. [PMID: 33489003 PMCID: PMC7790738 DOI: 10.1016/j.csbj.2020.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/16/2022] Open
Abstract
Ticks are arthropod ectoparasites and vectors of pathogens affecting human and animal health worldwide. The exoskeleton is a structure that protect arthropods from natural threats such as predators and diseases. Both structural proteins and chemical elements are components of the exoskeleton. However, the chemical composition and effect of pathogen infection on tick exoskeleton properties has not been characterized. In this study, we characterized the chemical composition of tick exoskeleton and the effect of Anaplasma pathogen infection on the chemical elements of the exoskeleton and selected structural proteins. The chemical composition was characterized ventral, dorsal upper and dorsal lower regions of tick exoskeleton by scanning electron microscopy and energy dispersive spectroscopy and compared between infected and uninfected ticks. The levels of selected structural proteins were analyzed in infected and uninfected I. scapularis salivary glands by immunofluorescence analysis. The results showed that tick exoskeleton contains chemical elements also found in other arthropods. Some of the identified elements such as Mg and Al may be involved in tick exoskeleton stabilization through biomineralization of structural proteins that may be overrepresented in response to pathogen infection. These results suggested that pathogen infection alters the chemical composition of tick exoskeleton by mechanisms still to be characterized and with tick species and exoskeleton region-specific differences.
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Affiliation(s)
- José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real, Spain.,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - José Francisco Lima-Barbero
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real, Spain
| | - Eduardo Prado
- Department of Applied Physics, Faculty of Chemical Sciences and Technologies, Universidad de Castilla-La Mancha, Avda. Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - Iván Pacheco
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real, Spain
| | - Pilar Alberdi
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real, Spain
| | - Margarita Villar
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM), Ronda de Toledo s/n, 13005 Ciudad Real, Spain
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